Context :

Aims : We present a ground-based , near-infrared search for lensed supernovae behind the massive cluster Abell 1689 at z = 0.18 , which is one of the most powerful gravitational telescopes that nature provides .

Methods : Our survey was based on multi-epoch J -band observations with the HAWK-I instrument on VLT , with supporting optical data from the Nordic Optical Telescope .

Results : Our search resulted in the discovery of five photometrically classified , core-collapse supernovae with high redshifts of 0.671 < z < 1.703 and magnifications in the range \Delta m = -0.31 to -1.58 mag , as calculated from lensing models in the literature .
Owing to the power of the lensing cluster , the survey had the sensitivity to detect supernovae up to very high redshifts , z \sim 3 , albeit for a limited region of space .
We present a study of the core-collapse supernova rates for 0.4 \leq z < 2.9 , and find good agreement with previous estimates and predictions from star formation history .
During our survey , we also discovered two Type Ia supernovae in A1689 cluster members , which allowed us to determine the cluster Ia rate to be 0.14 ^ { +0.19 } _ { -0.09 } \pm 0.01 SNuB h ^ { 2 } ( SNuB \equiv 10 ^ { -12 } SNe L ^ { -1 } _ { \odot,B } yr ^ { -1 } ) , where the error bars indicate 1 \sigma confidence intervals , statistical and systematic , respectively .
The cluster rate normalized by the stellar mass is 0.10 ^ { +0.13 } _ { -0.06 } \pm 0.02 in SNuM h ^ { 2 } ( SNuM \equiv 10 ^ { -12 } SNe M ^ { -1 } _ { \odot } yr ^ { -1 } ) .
Furthermore , we explore the optimal future survey for improving the core-collapse supernova rate measurements at z \gtrsim 2 using gravitational telescopes , and for detections with multiply lensed images , and we find that the planned WFIRST space mission has excellent prospects .

Conclusions : Massive clusters can be used as gravitational telescopes to significantly expand the survey range of supernova searches , with important implications for the study of the high- z transient universe .